const ages : number [] = [18, 19];
let array1 : number [] = [1, 2, 3, 4, 5];
let a1 : number = array1 [1];
console.log (a1);
let array2 : number [] [] = [[1, 2, 3], [3, 4], [5]];
let a2 : number [] = array2 [1];
let a3 : number = array2 [1] [1];
let a4 : number = a2 [1];
console.log (a2);
console.log (a3);
console.log (a4);
